Two-dimensional scintillation neutron detectors for the extension of SENJU diffractometer

Nakamura, Tatsuya  ; To, Kentaro  ; Koizumi, Tomokatsu; Kiyanagi, Ryoji  ; Ohara, Takashi   ; Ebine, Masumi ; Sakasai, Kaoru  

Two-dimensional neutron detectors were developed for the extension of SENJU time-of-flight Laue single crystal neutron diffractometer in J-PARC MLF. The detectors are to be installed at the additional detector bank for the SENJU instrument. The detector module is made based on ZnS scintillator and wavelength-shifting fiber technology, where each detector module maintains a neutron-sensitive area of 256256 mm with a pixel size of 44 mm. To meet the tight space limitation in the instrument, the detector was designed as compact as possible. The detector has a depth of 170 mm, which is about 40% smaller than that of the original SENJU detector. All four produced detectors exhibited similar detector performances: detection efficiency 50-60% for 2- neutron, Co gamma-ray sensitivity 110, count uniformity 3-6%.